Autism and Pervasive Developmental Disorder - Not Otherwise Specified (a mild form of autistic spectrum disorder), are heterogeneous conditions that affect about 15-40 per 10,000 children. Boys are affected about four times more frequently than girls. The racial and social class incidence of autism is similar. Autism is a life long condition and people with autism often require full-time care and supervision. Autism places a considerable burden of care on the family and society. The current focus in etiology of autism lies in developmental abnormalities of the limbic system and cerebellar-cortical connections. However, it seems likely that autistic behaviors may be caused through several mechanisms. Pharmacological treatment has generated some useful adjuncts to behavioral intervention but has not been associated with any primary change in the core symptoms of autism. Over the last year or so, many families of children with autism have sought an infusion of the intestinal hormone, secretin (usually used in diagnostic endoscopic procedures). Anecdotes from this experience are diverse but it does seem that a subsection of children with autism are truly helped, some remarkably so, by this infusion. Secretin therapy has now gained national media coverage and large numbers of children are now receiving secretin infusions, usually in private clinics. There has been neither a controlled study of the usefulness of secretin nor a study of the mechanism of action of secretin in this disorder. It is not known which children are more likely to show responsiveness to secretin. There is a need for a major pediatric institution to take leadership on these issues.